1. Field of the Invention
The present invention relates to a digital electronic camera and the interfacing of the camera to an external processing device which monitors, receives images and/or audio, and/or controls the camera through an input/output interface. The invention is more particularly related to a digital electronic camera which automatically detects a connection to the external processing device.
2. Discussion of the Background
Conventional cameras which use light sensitive film have been known for a long time and the manner of generating images is well-known; light sensitive photographic film is exposed to light which passes through a lens and a shutter. The film is then taken to a developing center and processed into photographic prints.
Digital electronic cameras which electronically capture images or images along with audio are also known. However, this field of technology is relatively new and there is not a universal standard for exporting or producing images from digital cameras. When designing the camera corresponding to the present invention, the inventors have discovered various problems in communicating information out of the camera. These problems include the connection of the camera to an external device such as another camera or a general purpose computer. The present inventors have sought to overcome problems pertaining to the actual connection of the camera to the external device, the conversion of signal levels from a level used by the processor within the camera to a level compatible with a communication interface, the detection of a connection of the camera to the external device, and the manner of assembling the information to be transmitted.
Accordingly, one object of the present invention is to provide an electronic camera capable of detecting that there is a proper connection and communication with an external device such as a computer. It is a further object of the invention for the camera to transmit and receive images and/or audio from the external device after the connection has been established. It is yet another object of the invention to provide an electronic camera which operates without utilizing an electrical-mechanical switch for placing the camera in a communication mode. It is yet another object of the invention to provide an electronic camera which operates using a single switch to control both whether the camera plays images and records images when the external device is not detected to be connected, and which also controls whether the camera transmits or receives images when the external device is determined to be properly connected to the camera.
These and other objects are accomplished by an electronic camera for connection to an external device such as a personal computer. The electronic camera periodically checks, for example, every one-half to one second, whether the camera is connected to the external device and also whether the external device is in a state which permits communication. After it is determined that there is a proper connection and the external device is in a state which permits communication, there is a communication between the electronic camera and the external device of images and/or audio.
Preferably, the camera detects proper connection to the external device and that the external device is in a state which permits communication by monitoring a data terminal ready (DTR) signal of an RS-232 connection. This DTR signal will indicate both that the external device is properly connected and ready to communicate.
In an embodiment of the invention, the camera includes a single switch for both controlling whether the camera captures images through the lens or plays images back to the user on a video screen, and whether the camera is to transmit or receive images and/or audio or transmit the images and/or audio when the external device is detected to be connected and capable of communicating. By detecting that the external device is capable of communicating, it is possible to eliminate a separate switch which places the camera in a communication mode.